Acoustical instrument.



L. LU MIBRE.

AGOUSTIOAL INSTRUMENT.

APPLICATION FILED MAY1B,1010,

1 ,O'72A77, Patented Sept. 9, 1913.

. Lou/lifjulin'e/"a WI/7165505: WJvmZZZmM MM UNITED STATES "PATENT OFFICE. I

LOUIS LUliEIERE, 0F LYON, FRANCE, ASSIGNOR TO VICTOR TALKING MACHINE COM- PANY, OF CAMDEN, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ACOUSTICAL INSTRU ENT.

T 0 all whom it may concern Be it known that I, Louis LUMIERE, a citizen of the Republic of France, residing at Lyon, in the Republic of France, have invented certain new and useful Improvements in Acoustical Instruments, of which the following is a full, clear, and complete disclosure. p

This invention relates to improvementsin acoustical instruments such as telephones, microphones, Stethoscopes, talking ma.- chines, musical instruments, and in general any instrument used for the reception or transmission of sounds.

The invention consists. in acertain construction of sound box for such instruments, the details of which will be given below.

The essential features of the invention arean extensible chamber with a stationary wall, a movable wall adapted to be reciprocated toward and away from the stationary wall, and .means between the two walls for preventing the escape of air between them but allowing perfect freedom of the movable wall to move in unchanged form and to any extent that may be practically required.

According to this invention a sound box for acoustical instruments is obtained comprising a stationary .wall, having an opening therein for the passage of the sound waves, a movablewall adapted to be reciprocated toward and away from the station my wall, and means between the edges of the movable wall and the stationary wall to prevent the escape of air between them, such means, however, leaving the movable wall free to move as a whole in substantially unchanged form to any extent that may practically be required, and ofiering substantially no resistance to the movement of the movable wall whatever the position of the latter with regard to the stationary wall, so that the position and movementof the movable 'wall is regulated entirely by the sound waves or means through-which the movable wall is reciprocated. Further,.according to this invention the whole of one side of the extensible chamber moves, and not merely the central portion thereof, thus producing a more effective reproduction.

In the accompanying drawing the inven-- 'tion is illustrated as applied to,the sound box of a talking machine.

Figure 1 1s a sectional elevation of one Specification oi Letters Patent.

Application filed my 18, 1910. Serial No. 561,928.

Patented Sept. 9, 1913.

construction of talki machine sound box embodying the invention; F ig. 2 a similar view of the modified form of this invention. Fig. 3 is a similar view of a further modification of this invention. Fig. 4: illustrates a modified form of this invention which has been found of value for obtaining rigidity in the. movable wall; Fig. 5 shows afurther modified construction of this invention for the same purpose.

The sound boxes which are usually employed in talking machines andmany other acoustical instruments are at. present constructed with a chamber closed upon oneterial, is set in vibration in the case of tall in-g machines by means of-a suitabletrans mitting device connecting it with the needle or sapphire, which follows the groove in the disk or cylinder carrying the phonogram. In this arrangement, certain effects due to the elasticity of the diaphragm and the formation. of nodal lines render unnatural the quality of the sound obtained and limit the practical dimensions of the apparatus.

The sound box forming the subject of thisinvention does not present these objections, consisting as it does of an extensible chamber closed upon its two opposite sides by rigid walls which can approach or recede from one another. These opposite sides may be. connected together and the space between them closed in :1 substantially air tight manner by a suitable intcgumental mounting, and in this form of my invention that may be united by means of a flexible folding joint of any suitable thin inelastic, solid material in the manner of abellows or accordion. I may, however, dispense with the said flexible mounting between the said walls and arrange one wall to slide within the other like a piston.

Under the action of the stylus following the pho-nographic sound line, the said walls are caused to approach or rccede from one another, and these movements produce variations of the pressure of the air within the sound box. It is these variations which are the essential cause of the prcduction of sound. The interior of the sound box so constructed may be connected to an amplifying horn as in other well'known apparatus.

the said closure, and the, fold of the closure will be disposed at an'angle to the plane of the movable wall when unstressed. When the movable wall is vibrated, however, to cause it to approach and recede from the stationary wall, said, closure will vary in distance from the axis of the sound box,

. changing or altering its position and shape without being extended or stretched. The side at is stationary, its mass being suflicient to give it considerable inertia relatively to the movablepar ts of the sound box. The

side 12, on the other hand, is very light, and

is connected with the stylus c by means of the stylus bard, which amplifies the movements of the stylus. The interior of the sound box connects with the amplifying horn of the machine through the opening f. The material e extends around three sides of the sound box, the movable wall I) being hinged to the stationary side a at the top by a suitable flexible joint;

The arrangement shown'in Fig. 2 differsfrom that illustrated in Fig. 1 only in that the material e in this construction extends around the whole perimeter of the sides a and I). These sides are arranged parallel.

to one another and they may be circular or of any other convenient form.

It is pointed out that the flexible connection which, according to the present invention, is used between the movable wall and the stationary wall of the sound box occupies a position in which the movement of the movable wall occasions practically no strain or tension whatever to be putnpon the flexible connection, and that consequently there is practically no resistance to be overcome by the movable -wall in" follow- D ing the vibrations of the stylus. In this respect the present invention differs'materially' 'frompreviously known constructions of sound box, and in particular from the construction in which a rigid diaphragm is fur.-

nished with a surrounding border of flexible or elastic material such as membrane or rubber, which lies in substantially'the same plane as the diaphragm, i. 6., in a plane at right angles to the direction of the vibrations of the diaphragm, or movable wall.

This annular border is held between the diaphragm on one side and some such device as clamping rings on the other side. If the clamping rings are close to the edge of the diaphragm, the flexible connection will not be of sufficient extent to allow of entire freedom ofmovement of the diaphragm without some strain or tension being put upon the flexible connect-ion; if some distance isa satisfactory and eflicient reproduction is impossible, as an escape of air at the edges results in less efficient reproduction.

In Fig. 3 is illustrated a construction in which the folding joint ve is replaced by a rubber packing g adapted to roll between the cylindrical surfaces of the two sides a and b. This rubber packing is made to lie lightly between the two== surfaces so as to be only just in contact therewith and at the same time effect a completeclosure.

The friction between the rubber and contacting surfaces is reduced to a minimumv owing to the rolling action of the rubber packing. Moreover, the resistance to be overcome is practically constant whatever the extent of the movement of the movable wall. It'is evident that any other system of movable joint offering no appreciable resistance may be employed for attaining the desired end. In. order to obtain simultaneously suflicient rigidity and lightness in the movable'side b, so thatit will reciprocate in practically unchanged form, it is found desirable 'to construct this side of very thin metal and to render it rigid by stamping it out in some such form as. those shown by way of example in Figs. 4: and 5 of-the ac companying drawings.

In Fig. 4 the movable wall is dished in] shape, the side I) being stamped in the form of a spherical cup, thus providing a surface, the parts of which lie'in difierent planes,

and is further reinforced around its periph ery by a raised edge or flange h. The side a .is recessed to have a profile which may be made to conform or follow substantially the contour of the adjacent side of the movable wall, but the said side or wall a is not necessarily identical with or parallel to that of the side I). The diameter of the movable wall I), however, should be as great as that of the adjoining opening in the stationary wall; that is to. say, as great in diameter as the diameter of the concave face of the movable wall I). The raised edge h may be turned toward either the convex or the concave side of the movable wall 12. It has been found that good results are obtained with a box of the following dimensions.- For the.

diameter of the cup 6. The connecting strip 6 may be made for instance of go-ldbeaters skin, or very thin paper, or any other substance which offers a minimum of resistance to folding and possesses but. very little resiliency of its own. The strip e may conveniently be attached to'the two surfaces a and 6 held at a fixed distance apart, and when it has properly adhered, the two walls a and b may be brought closer together to the posit-ion they occupy in actual use, and the slack of the connecting material pressed gently inward between the two. With this arrangement, the slightest movement of the .wall 6 toward the wall a produces a compression throughout the entire chamber. The spherical cup form shown in Fig. 4 may be altered to a parabolic form, or to that of a right circular cone, 'or generally speaking to any form which will give rigidity to the side I). This rigidity may also be obtained by means of moldings or corrugations arranged radially as indicated in Fig. 5. The stationary massive side a may be given any suitable form, and may form the counter part to the movable side 6. It is to be understood that this construction of the movable side may be applied to all forms of sound box mentioned above.

Having thus described my invention, what I claim and desire to protect by Letters Patent of the United States, is

1. A sound box for acoustical instruments comprising a stationary wall, a movable wall, means for reciprocating the movable wall toward and away from the stationary wall, and flexible inelastic means uniting the two walls and completing the chamber of the sound box, but having substantially no appreciable influence on the position of thte movable wall relatively to the stationary wall within the ordinary range of the movement of the movable wall.

2. A sound box for acoustical instruments comprising a stationary Wall, a movable wall, means for reciprocating the movable wall toward and away from the stationary wall, and yielding, inelastic, folding means uniting the two walls and completing the chamber of the sound box, but having substantially no appreciable influence on the positions of the movable wall relatively to the stationary wall within the ordinary range of the movement of the movable Wall, and leaving the movable wall practically free to move as a whole in substantially unchanged form to any extent that may be practically required, and offering substantially no resistance to the movement of the movable wall, whatever the position of the latter may be with respect to the stationary wall within the limits of the movement of said movable wall.

3. A sound box for acoustical instruments comprising a stationary wall, a rigid movable wall adapted to be reciprocated toward and away from the stationary wall in substantially unchanged form, and means forming a flexible, folding, inelastic joint between the two walls which allows practically free movement of the movable wall in unchanged form within the limits of the movement of said movable wall.

4. A sound box comprising a stationary wall, a movable wall and means in the form of a yielding accordion plait connecting said stationary wall to said movable wall.

5. A sound box for acoustical instruments comprising a rigid movable wall of dished form, a stationary wall, a folding, inelastic, flexible means uniting the two walls and completing the chamber of the sound box, but having substantially no appreciable influence on the position of the movable wall relatively to the stationary wall within the ordinary range of operation of the device.

6. A sound box for acoustical instruments comprising a stationary wall, a movable wall means for reciprocating the movable wall toward and away from the stationary wall and means in the form of an accordion plait between the two walls forming a closure at their perimeter-s and completing the chamber of the sound box but having practically no appreciable influence on the position of the movable wall relatively to the stationary wall within an ordinary range of operation of the device.

7. In a sound box, the combination with a stationary wall of a movable wall, and means connecting said walls and forming with said walls an inelastic flexible folding closure.

8. Ina sound box, a fixed wall, a movable wall, and an integumental mounting for said movable wall attached thereto and offering substantially no resistance to reciprocatory movements of said movable wall under normal conditions.

9. In a sound box for acoustical instruments, a relatively stationary wall, a movable wall, a memberarranged to reciprocate said movable wall and a closure of yielding,

.solid material attached to both of said walls, the movable Wall being held in operative po- SItlOII solely by the member reciprocating the same. I

10. In a sound box for a oustical instruments a relatively stationary wall, a movable wall, a closure of yielding, solid material for the space therebetween attached to both of said walls, and a member wholly controlling thenposition and movement of the movable wa 11. In a sound box for acoustical instruments, a relatively stationary wall, a movable wall, and a normally folded closure forthe space therebetween adapted to permit uninfluenced the motion of the movable wall.

12. In a sound box for acoustical instruments, a relatively stationarywall, a movable comparatively rigid wall and a flexible normally folded closure arranged in the space therebetween to which the stationary wall and the movable Wall are attached.

13.. A sound box for acoustical instru-' stationary wall, and a flexible, folding clo-v sure for the space between said walls arranged and adapted to permit uninfluenced the movement of the said movable wall, the movable wall being of as great diameter as the diameter of the said opening' 15. A sound box for acoustical instruments comprising a relatively stationary wall, a rigid movable wall and a folding closure for the space therebetween, which, as the movable'wall approaches and recedes from the stationary wall, varies its minimum distance from the axis of the sound box.

16. A sound box for acoustical instruments comprising a relatively fixed wall and a chamber of which the sides are formed by said relatively fixed wall and a movablewall, while the edge of the chamber is formed by a closure disposed between the said two walls and adapted to exercise a compressing action upon the air in the space between the two walls upon reciprocation of the movable wall toward the fixed wall, but not to restrain the free movement of the movable wall.

17 A sound box for acoustical instruments, comprising a movable wall and a relatively stationary wall forming normally substantially parallel adjoining surfaces, one permanently concave and the other permanently convex, and means for reciprocating said movable wall in accordance with a sound record.

18. A sound box comprising a stationary wall, a wall movable toward and away from said stationary wall, means for reciprocating said movable wall toward and away from said stationary wall, and normally folded means connecting said walls and forming therewith an inclosure said folded means being arranged and adapted to per mit the substantially free movement of said movable Wall in any direction' 1 19. In a sound box, the combination with a relatively stationary wall, of a movable Y diaphragm, and solid flexible means con-- 'necting said diaphragm to said wall and arranged to permit substantially free movement of said diaphragm in any direction.

20. In a sound box, the combination with a relatively stationary wall, of a movable diaphragm, and solid normally folded flexible means connecting said diaphragm to said wall and arranged to permit substantially freemovement of said diaphragm in any direction.

21. In a sound box, the combination with a relatively stationary wall, of a movable diaphragm, and solid flexible means connecting said diaphragm to said wall, said means being provided with an annular fold spaced between said diaphragm and said wall and arranged to permit substantially free move ment of said diaphragm in any direction with respect tosaid wall.

22. A movable wall, a fixed wall, a closure attached to both of said walls comprising v relatively movable elements, said elementsbeing re-positioned during the movement of said movable Wall by substantially only bodily movements of said elements.

Inwitness whereof I have hereunto set my hand this 26th day of April, A. D. 1910.

' LOUIS LUMIERE.

Witnesses: I

- GASTON JEANNIAUX,

MARIN VACHON. 

